The research program is concerned with problems of structure and function of the nervous system. Major emphasis is on the study of peripheral and central mechanisms of sensory systems, including audition, vision, somesthesis and olfaction. Particular attention is given to specifying the topographical organization and structural and connectional features within each system. Coding of sensory information by spike discharge patterns at peripheral and central levels within each system is of special interest. Physiological studies of regulatory pathways within the hypothalamus are also under way, as are studies of anatomical and functional connections of other neural circuits in the thalamus and brainstem. The methods used are multidisciplinary. Single-unit recordings, evoked potentials and electrical stimulation are used in electrophysiological studies. Great care is taken to control the parameters of stimulation for each sensory system. Electrophysiological mapping procedures and histological identification of recording sites are important in localizing functions to structures. Computers are extensively used in collecting and analyzing data. Mossbauer and laser techniques, tissue culture methods, dye-injection of single neurons, intracellular recording, modeling methods and the ontogenetic approach are applied in different projects. The approach in general is comparative, employing a variety of mammals. Acute anesthetized and chronic unanesthetized preparations and sterile neurosurgical techniques are employed. Behavioral studies are used when necessary to clarify function of neural circuits. Several anatomical methods are employed to clarify fine structural features of receptors, synapses and details of structure and connectivity. These include special histological and staining procedures, quantitative neuroanatomical methods, autoradiography, histochemical tract-tracing methods and electron microscopy.